The Nuclear Medicine Core will provide critical support for the work of the three clinical projects in the treatment of lymphoma and leukemia with I-131 labeled monoclonal antibodies. The specific aims are 1) to prepare I-131 labeled antibodies suitable for the initial diagnostic and dosimetric studies of patients entering the study protocols, 2) to collect data by serial gamma camera imaging, whole body counting, analysis of blood, urine and tissue samples to be used for estimations of internal radiation absorbed dose, 3) to derive meaningful estimates of internal radiation dosimetry for individual patients and 4) to prepare and administer high dose (300 or more mCi) I-131 labeled antibody preparations for therapy. These studies will be done in the protein labeling laboratories, Nuclear Medicine Clinics of the Division of Nuclear Medicine and the Oncology Ward of the University Hospital. Low and high dose I-131 labeling will be done initially by electrophilic methods though alternate methods may be used as they are developed through other research programs in the Division of Nuclear Medicine.